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If (a_n=n^3+2n^2-n) then what is the value of (a_4)?
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Answer and explanation
Correct answer: 92
Given (a_n=n^3+2n^2-n), substitute n=4: (a_4=4^3+2(4^2)-4=64+32-4=92). Therefore, 92 is the correct option. A value such as 94 can result from an error while subtracting the final 4. Exam tip: Substitute the value of n carefully into every term of the rule.
Frequently asked questions
What is the correct answer to this question?
92
Why is this the correct answer?
Given (a_n=n^3+2n^2-n), substitute n=4: (a_4=4^3+2(4^2)-4=64+32-4=92). Therefore, 92 is the correct option. A value such as 94 can result from an error while subtracting the final 4. Exam tip: Substitute the value of n carefully into every term of the rule.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Explicit or general rule.
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